We have a large outdoor deck with a sliding door at each end. At each door, in the interior are two switches. One is an old intermatic timer. The other is a traditional Decora. The previous owners left a great reference guide in the electrical room detailing all the circuits, lights, plugs and breakers. All typed up...looks professionally done. The switches in question are listed as “2W deck lights with timer”.

There is wiring for deck lights but no lights. I’ve purchased lights which I hope to install. Id also like to replace the old timer and put in a 3 way switch there so the lights can be operated from either sliding door.

Opened things up today. I was surprised to find the decora switch was not a 3 way. It has 2 black wires connected to the bottom and the red at the top. You can see how the old internmatic is wired.

1. How would I wire the new 3 way switch where the old intermatic is?
2. Is the existing decora wired correctly to work as a 3 way once I replace the intermatic With a 3-way? If not, do I need to replace the decora with a 3 way? How would that be wired?

Thanks
J

 

Look into the box where the regular switch is...... do a red and a black wire that's on that switch go into one cable ? If yes..... those should be the travelers and the remaining black would be the common.

 

Yes, the red and black are together. Does that mean I can use this as a 3 way, or do I need to replace it with a 3 way switch?

 

That looks like a single pole was put in there to operate the lights in tandem with the timer.
You'd need to replace that switch with a three switch.